In general, a cross-correlation technology using multiple array antennas is a technology that is generally applied in the signal processing fields, such as digital beam forming and direction detection technologies using phase delay factors that evaluate signal arrival direction in the configuration of a radio receiving apparatus. Spatial modeling of an arrival signal through a correlation technique is to evaluate signal arrival direction estimation parameters for maximizing signal power by extracting a characteristic value for an array antenna response characteristic of the arrival signal or digitally adding a phase delay value to an antenna with respect to the signal arrival direction.
FIG. 1 is a diagram illustrating the configuration of a dual channel direction detection apparatus using a multi-band array antenna in the related art, and may include an array antenna 100, an array antenna selection unit 102, and a sequential channel multiplex 104.
In the dual channel direction detection apparatus as illustrated in FIG. 1, however, spatial filtering and signal arrival direction estimation through beam forming using the array antenna 100 requires configuration of a digitizer for signals from a plurality of spatial array antennas and a device for multi-channel phase synchronization for sampling time, that is, sampling clock, for signal collection, and it is required to use phase correction technology or the like using a correction signal for a multi-channel reception channel path to perform such operations.
In general, phase delay parameter values of respective antenna responses in the signal arrival direction may be extracted with respect to sampling-synchronized signals that are received from a plurality of array antennas, or in contrast, signal spectrum measurement through the beam forming may be performed through application of the phase delay parameters of the extracted array antenna responses.
The array antenna configuration has the problem that it may accompany performance deterioration due to the radio shield phenomenon of an antenna mast for supporting the array antenna or antenna elements. Accordingly, in the radio measurement system for the signal spectrum measurement and signal direction estimation, a reference receiving channel is selected, and the measurement is performed using correlations in amplitude, phase, and time delay between the signal characteristics of the reference receiving channel and the signal characteristics of receiving channels of other array antennas.
However, it is inefficient in space and cost to configure a radio receiving apparatus that is composed of a plurality of receiving channels corresponding to antenna channels in the radio measurement system.
Further, if the received signal characteristics of the reference receiving channel are not satisfactory due to the radio wave shadow of the antenna or the mast, the overall radio measurement is affected thereby.